PM / OPP: Remove ARCH_HAS_OPP

Since the OPP layer is a kernel library which has been converted to be
directly selectable by its callers rather than user selectable and
requiring architectures to enable it explicitly the ARCH_HAS_OPP symbol
has become redundant and can be removed. Do so.

Signed-off-by: Mark Brown <broonie@linaro.org>
Reviewed-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Nishanth Menon <nm@ti.com>
Acked-by: Rob Herring <robh@kernel.org>
Acked-by: Shawn Guo <shawn.guo@freescale.com>
Acked-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

kernel/power/Kconfig

@@ -253,9 +253,6 @@ config APM_EMULATION
 	  anything, try disabling/enabling this option (or disabling/enabling
 	  APM in your BIOS).
 
-config ARCH_HAS_OPP
-	bool
-
 config PM_OPP
 	bool
 	---help---